code: def _get_n_features(model):
      return model.n_features_in_
  
file_path: hummingbird/hummingbird/ml/operator_converters/sklearn/gbdt.py
imports: import numpy
  from onnxconverter_common.registration import register_converter
  from ..None import constants
  from .._gbdt_commons import convert_gbdt_common, convert_gbdt_classifier_common
  from .._tree_commons import get_parameters_for_sklearn_common, get_parameters_for_tree_trav_sklearn, TreeParameters
label_desc: Use image node_id 1 for calling a global function with example usage: _get_n_features(model) and returns: model